Airway Dimensions In Children Research Articles

Determining normal values for lower trachea and bronchi size in children by computed tomography (CT).

Normative data for central airway dimensions are a prerequisite to objectively assess large airway pathologies. Studies with computed tomography (CT) measurements of normal trachea and bronchi size in children are scarce. The purpose of this study is to establish normal values of central airway dimensions in children by CT. The study included chest CT studies from children aged 0-18 years. Any condition that predisposed the patient to have an abnormal tracheal or bronchial size was excluded. Airway diameters and cross-sectional area (CSA) were measured using double oblique reconstructions at five levels: proximal trachea, mid-trachea, distal trachea, right main bronchus, and left main bronchus. The inclusion criteria were met by 110 subjects (mean age, 10.8 years; SD, 5.2 years). Various regression models that considered the relationship between patient demographics and anteroposterior (AP) diameter, transverse diameter, and CSA at each of the five levels were assessed. R2 was utilized to select the best model. Multiple formulae (using patient age) were developed to calculate expected normal dimensions for five levels in the central airways on the natural log scale. Finally, z-scores were obtained for central airway dimensions at these five levels. Normative data in pediatric central airways are crucial to identify large airway pathologies. We propose using the formulae devised in our study to calculate the predicted dimensions of central airways and their z-scores in pediatric patients. Normative data from our study will aid in objective quantification of central airways, increase clinician confidence, and provide appropriate patient care.

The effect of maxillary protraction, with or without rapid palatal expansion, on airway dimensions: A systematic review and meta-analysis.

The use of maxillary protraction appliances (MPAs) and Facemask (FM), with or without a rapid maxillary expansion (RME), have become a routine orthopaedic treatment procedure for the treatment of Class III in growing individuals; several authors have suggested that maxillary protraction could have a positive impact on airway dimensions. The purpose of this systematic review and meta-analysis was to assess the efficacy of maxillary protraction appliances (MPAs), with or without a rapid maxillary expansion (RME), on airway dimensions in children in mixed or early permanent dentition. An electronic search was performed on PubMed, Medline, Scopus, The Cochrane Library, EMBASE and the System for Information on Grey Literature in Europe until November 30th, 2019. The Newcastle-Ottawa (NOS) scale was used to assess the studies' quality. Review Manager 5.3 (provided by the Cochrane Collaboration) was used to synthesize the effects on airway dimensions. After full text assessment, 8 studies were included in the qualitative and quantitative synthesis. NOS scores ranged 6 to 9 indicating high quality. The effects of two therapeutic protocols were compared, treatment with MPAs only (113 subjects treated - 65 controls) and the treatment with MPAs + RME (137 subjects treated- 87 controls). The MPAs only treatment group displayed a significantly increase in nasopharyngeal airway dimension at PNS-AD1 (random: mean difference, 1.39 mm, 95% CI, 0.32 mm, 2.47 mm, p= 0.01) and at PNS-AD2 (random: mean difference, 1.70 mm, 95% CI, 1.14 mm, 2.26 mm, p= 0.00001). No statistically significant changes were found post treatment in MPAs + RME treatment groups at PNS-AD1 (P= 0.15), PNS-AD2 (P= 0.17), McNamara's upper pharynx (MPAs + RME P= 0.05, MPAs P= 0.99) and McNamara lower pharynx (MPAs + RME P= 0.25, MPAs P= 0.40). MPAs only treatment can increase the pharyngeal thickness after treatment both at PNS-A1 and PNS-AD2. MPA+ RME had no effect on sagittal widths compared with controls, but the effect on the transverse dimension could not be assessed.

Dimensional compatibility of balloon-tipped bronchial blockers with the pediatric airway anatomy using different recommendations for age-related size selection.

Age-related recommendations for size selection of bronchial blocker devices are based on a few dated anatomical autopsy and radiological studies determining lower airway dimensions in children. These recommendations are based on anterior-posterior internal bronchial diameters, which are smaller than the more relevant lateral internal bronchial diameters. Outer diameters of bronchial blocker balloons inflated with the maximum recommended volume of air were compared to age-related lateral internal bronchial diameters of left and right proximal mainstem bronchi using five different recommendations for age-related size selection of bronchial blocker equipment in children published in the literature. The ratio of outer bronchial blocker diameters inflated with the maximal recommended volume of air to the median lateral internal diameters of the proximal mainstem bronchus ranged from 71.4% to 181.8% for the left side and from 61.7% to 162.6% for the right side. There were many settings where the blocker diameters did not reach the median lateral internal diameters of the proximal mainstem bronchus. This was more often observed for the right than for the left side (37 vs 22 settings). This analysis demonstrates that irrespective of the recommendation for size selection used, neither the two balloon-tipped vascular catheters included nor the Arndt endobronchial blockers are ideal for lung isolation in children are compared with the age-related relevant dimensions of pediatric airway anatomy. A redesign of bronchial blocker equipment with age-related anatomically based high-volume, low-pressure blocker balloons made from ultrathin membranes and with smaller catheters would be desirable.

Developmental changes of upper airway dimensions in children.

Knowledge about airway dimensions during child growth is of paramount importance for pediatric clinical practice. Decisions about airway management in children are based on relatively limited, imprecise, or incomplete data about airway size. The aim of this work was to determine the anatomical development and size of airway structures from birth to adolescence using high-resolution computed tomography scans and to study the correlation between airway measurements and biometric data. We conducted a retrospective study of all high-resolution computed tomographyscans including the respiratory tract, performed in our tertiary pediatric center (for reasons unrelated to airway symptoms) between June 1, 2016, and October 15, 2017, on children aged from 1day to 14years old. On each scan, 23 measurements of the larynx, trachea, and mainstem bronchi were performed. Patients were stratified into 16 groups according to their age. We calculated median value for each measurement in each group. Statistical models were calculated to explore correlation between measurements and age or weight. A total of 192 scans were included (127 boys/65 girls). The mean age was 7years. The correlations between airway measurements and age or weight were always significant. The relationship between measurements and age was found to be suitably represented by a cubic polynomial equation suggesting that the airway has a rapid growth phase in the first 3years, followed by a slow growth phase and a second rapid growth phase during adolescence. The most relevant biometric parameter was age concerning 21 of the measurements. This comprehensive anatomical database of upper airway dimensions provides important data in the field of pediatric airway anatomy, particularly relating to the cricoid. We demonstrated that laryngeal, tracheal, and bronchial parameters correlate better to age and have three different growth phases.

Airway and hard tissue dimensions in children treated with early and later timed cervical headgear-a randomized controlled trial.

A Kloehn-type cervical headgear (CH) aims to correct skeletal jaw discrepancy in Class II children. A few studies have reported CH treatment effects on airway dimensions, but none of them have been randomized according to timing. To evaluate related craniofacial structures and pharyngeal airway dimensions in children with a Class II occlusion treated with CH and randomized into early and late treatment groups. Randomized, parallel-group, prospective controlled trial. The material comprised 67 seven-year-old children with a Class II occlusion. Sealed-envelope randomization in 1:1 ratio was used to divide the children into two equal groups. In the early group (EG, n = 33), CH treatment was started immediately or after eruption of the first maxillary molars. In the second, late group (LG, n = 34), the active CH treatment was started about one and half year later. The active CH treatment was continued in both groups until normal Class I occlusion on first molars was achieved. Cephalometric radiographs were taken from both groups at the beginning of follow-up (T0), at the beginning of CH treatment of the second group (T1), and at the end of CH treatment of the second group (T2). Changes in cephalometric measurements were used as primary outcomes. Blinding was applicable for outcome assessment. Fifty-six children completed the study. The posterior change in the position of the maxilla was significant for early treatment males at T0-T1 (SNA; P < 0.001, ANB; P = 0.009) and T0-T2 (SNA; P = 0.012). The palato-mandibular angle (PL-ML) decreased during T0-T1 in early treatment females (P = 0.018) and early treatment males (P = 0.037). The retroglossal airway increased (P = 0.010) in early treatment males at T0-T1. Highly significant positive correlations (P < 0.001) between skeletal and upper airway dimensions during early CH treatment were found in males. No harms were encountered. Despite the effective CH treatment, no harmful upper airway changes were found. NCT02010346.

Airway Dimensions in Children with Neurological Disabilities During Dexmedetomidine and Propofol Sedation for Magnetic Resonance Imaging Study.

Children with neurological disabilities are at an increased risk of airway complications during anaesthesia for magnetic resonance imaging (MRI) with spontaneous respiration. The primary objective of this study was to evaluate airway dimensions during propofol and dexmedetomidine sedation for MRI in children with neurological disabilities. The secondary objective was to examine the adverse respiratory and sedation-related events. Seventy-two children aged 1-6 years undergoing MRI were randomly selected to receive sedation with either 2 mg kg-1 h-1 of propofol or 2 μg kg-1 h-1 of dexmedetomidine. The airway dimensions were measured at soft palate, the base of tongue and mid-epiglottis. Adverse airway events were noted, and the quality of sedation was determined based on the need for dose modification, patient movement and repeat imaging requirements. There was no significant difference in airway dimensions observed between the dexmedetomidine and propofol groups, except for maximum and minimum transverse diameter (15.4±3.4 vs. 13.4±4.7, p=0.04 and 14.6±3.3 vs. 12.4±4.7, p=0.02 respectively) at soft palate and for cross sectional area difference at the base of tongue (14.5±13.9 vs. 20.1±19.3, p=0.03). Airway obstruction (2/36 vs. 3/36), apnoea (0/36 vs. 3/36) and desaturation (0/36 vs 2/36) occurred less frequently with dexmedetomidine. Additional requirement of sedation (6 vs. 3 patients; p=0.48), movement during imaging (9 vs. 5 patients; p=0.37) and poor image quality necessitating re-acquisition (4 vs. 0 patients; p=0.08) were more frequent with propofol. Airway dimensions were similar during dexmedetomidine and propofol sedation, except for the transverse diameters at soft palate, and for cross-sectional area difference at the base of tongue in spontaneously breathing children with neurological disabilities. Airway complications were less frequent and the quality of sedation was better with dexmedetomidine.

Lower airway dimensions in pediatric patients-A computed tomography study.

The aim of this study was to obtain lower airway dimensions in children by means of computed tomography (CT). Chest CT scans from 195 pediatric patients (118 boys/77 girls) aged 0.04-15.99 years were analyzed. Tracheal and bronchial lengths, anterior-posterior and lateral diameters, as well as cross-sectional area were assessed at the following levels: mid trachea, right proximal and distal bronchus, proximal bronchus intermedius, and left proximal and distal bronchus. Mediastinal angles of tracheal bifurcation were measured. Data were analyzed by means of linear and polynomial regression plots. The strongest correlations were found between tracheal and bronchial diameters and age as well as between tracheal and bronchial lengths and body length. All measured airway parameters correlated poorly to body weight. Bronchial angles revealed no association with patient's age, body length, or weight. This comprehensive anatomical database of lower airway dimensions demonstrates that tracheal and bronchial diameters correlate better to age, and that tracheal and bronchial length correlate better to body length. All measured airway parameters correlated poorly to body weight.

Upper airway changes in Pierre Robin sequence from childhood to adulthood

To investigate pharyngeal airway changes in patients with Pierre Robin sequence (PRS) longitudinally from childhood to adulthood. Cleft Lip and Palate Unit, Clinic of Orthodontics, University of Zurich. Twenty-four patients born between 1970 and 1990 with non-syndromic PRS. Lateral cephalograms at age 5 (T1), 10 (T2), 15 (T3) and 20 (T4)years were available. Variables describing pharyngeal airway dimensions, soft palate morphology, tongue and hyoid position, skeletal morphology and head posture were assessed. A significant increase in nasopharyngeal depth was found over the entire observation period (T1 10.7 to T4 19.1mm, p<0.001), especially between T2 and T3 (change 3.8mm, p<0.001), and was mainly due to adenoid recession (r=-0.75, p<0.001; variation explained by 56%). Increase in velopharyngeal depth mainly took place between T3 and T4 (change 2.3mm, p<0.01). It was due to more anterior tongue posture (r=0.65, p<0.001; 42.5% of variation explained), in turn allowing the soft palate to take a more vertical position (r=-0.52, p<0.001). Increase in oropharyngeal depth was associated with head extension and anterior mandibular positioning (36% of variation explained). However, significance was not reached (T1 8.3 to T4 9.8mm, p>0.05). Upper airway dimensions in children with PRS improve with time, except for the oropharyngeal airway. Despite large interindividual variation, the mean remained in the lower reaches of normality described in other studies. Thus, further research should investigate the prevalence of obstructive sleep apnoea in adults with PRS.

Pediatric Laryngeal Dimensions: An Age-Based Analysis

In children, the cricoid is considered the narrowest portion of the "funnel-shaped" airway. Growth and development lead to a transition to the more cylindrical adult airway. A number of airway decisions in pediatric airway practice are based on this transition from the pediatric to the adult airway. Our primary aim in this study was to measure airway dimensions in children of various ages. The measures of the glottis and cricoid regions were used to determine whether a transition from the funnel-shaped pediatric airway to the cylindrical adult airway could be identified based on images obtained from video bronchoscopy. One hundred thirty-five children (ASA physical status 1 or 2) aged 6 mo to 13 yr were enrolled for measurement of laryngeal dimensions, including cross-sectional area (G-CSA), anteroposterior and transverse diameters at the level of the glottis and the cricoid (C-CSA), using the video bronchoscopic technique under general anesthesia. Of the 135 children enrolled in the study, seven patients were excluded from the analysis mainly because of poor image quality. Of the 128 children studied (79 boys and 49 girls), mean values (+/-standard deviation) for the demographic data were age 5.9 (+/-3.3) yr, height 113.5 (+/-22.2) cm and weight 23.5 (+/-13) kg. Overall, the mean C-CSA was larger than the G-CSA (48.9 +/- 15.5 mm(2) vs 30 +/- 16.5 mm(2), respectively). This relationship was maintained throughout the study population starting from 6 mo of age (P < 0.001, r = 0.45, power = 1). The mean ratio for C-CSA: G-CSA was 2.1 +/- 1.2. There was a positive correlation between G- and the C-CSA versus age (r = 0.36, P < 0.001; r = 0.27, P = 0.001, respectively), height (r = 0.34, P < 0.001; r = 0.29, P < 0.001, respectively), and weight (r = 0.35, P < 0.001; r = 0.25, P = 0.003, respectively). No significant gender differences in the mean values of the studied variables were observed. In this study of infants and children, the glottis rather than cricoid was the narrowest portion of the pediatric airway. Similar to adults, the pediatric airway is more cylindrical than funnel shaped based on these video bronchoscopic images. Further studies are needed to determine whether these static airway measurements in anesthetized and paralyzed children reflect the dynamic characteristics of the glottis and cricoid in children.

Upper airway dimensions in children using rigid video‐bronchoscopy and a computer software: description of a measurement technique

Pediatric airway management decisions are based primarily on results derived from indirect measures of laryngeal and tracheal dimensions. More recent methods could provide more direct information about absolute and relative changes in airway dimensions associated with growth and development. The aims of this study were (i) to determine whether a 'video-bronchoscopic' measurement method could be used to reliably measure airway dimensions in children and (ii) to provide a preliminary assessment of dimensions of the glottis and cricoid in children of various ages. Following approval from the institutional review board, validation experiments were performed to determine whether measurements obtained from the video image from the bronchoscope provided accurate measurements of tubular objects of known dimensions. The reliability of the measurements was determined by using two independent trained observers to measure video-bronchoscopic images of the larynx at the level of the glottis and the cricoid in 11 children. The observers measured the video-bronchoscopic images and airway measurements were obtained in 16 additional children to determine the utility of the measurement method. There was good agreement between the direct and video-bronchoscopic measurement techniques (Bland and Altman plot) for both the cross-sectional area (CSA) and the diameter of objects. The interobserver measures for cricoid and glottis were reproducible as indicated by the concordance correlation coefficient (CCC) for cricoid anteroposterior diameter (CCC = 0.98, r = 0.98, accuracy = 0.99) and transverse diameter (CCC = 0.93, r = 0.8, accuracy = 0.99) as well as for the glottic anteroposterior diameter (r = 0.8, accuracy = 0.8, CCC = 0.6) and the glottic transverse diameter(r = 0.8, accuracy = 0.74, CCC = 0.6). Overall, for the 27 children studied [mean age 73 months (+/-24.7, range 30-140], the mean value of the cricoid CSA [45.3 mm(2) (+/-13.9)] was found to be greater than the glottic CSA [16.2 mm(2) (+/-10.1)]. The video-bronchoscopic imaging method provided an accurate, reliable measure of pediatric airway dimensions. This technique could be applied to assess absolute and relative airway size associated with growth and development. The relationship between glottic and cricoid dimensions during growth and development in children needs further investigation across various age groups.

Airway Geometry Models of Children's Lungs for Use in Dosimetry Modeling

Single-path whole-lung and lobar models of the lungs of 11 children between 3 mo and 21 yr of age were developed based on a combination of cast data and published information on distal airway dimensions. The cast data used to generate these models were taken from one of the largest databases of actual measurements in children. The methods used to develop the children's models were based on techniques that have been used to develop adult single-path airway geometry models. Model dimensions for the conducting airways, as well as the estimated dead space, for all children fell within the range of the limited published information. Thus, the method for estimating airway dimensions in adults may be successfully applied to develop estimates of airway dimensions in children. The predicted total lung capacity (TLC) for the older children (aged 8 to 21 yr) fell within or near the range arising from published scaling equations. The assumptions used to generate the gas exchange region for children 8 yr and older produced results that were reasonably consistent with available physiological data. However, these assumptions do not result in a physiologically consistent gas exchange region for children 3 yr of age and younger; also, to maintain physiologically reasonable relationships between dead space and alveolar volume, the models for children 3 yr of age and younger resulted in predicted TLCs well below those predicted using published scaling equations. These discrepancies may be reflective of dysanaptic growth, in which the alveolar region is growing more rapidly than the airways. The results for children 3 yr of age and under suggest the need for a greater understanding of lung development during this critical period. This is particularly important considering the increasing evidence that exposure to pollutants and other toxicants and allergens during the first 2 yr of life may have long-term consequences on respiratory disease outcomes. Our results suggest that the geometry model airway dimensions for all ages are appropriate for use with dosimetry models, but dosimetry modelers need to assess carefully the reasonableness of TLC and functional residual capacity volumes to which airway dimensions are scaled for children 3 yr of age and under.

Linear airway dimensions in children: including those from cleft palate.

Linear airway dimensions from incisor teeth to vocal cords were measured from radiographs. Normal children were slightly taller and heavier than children being treated for cleft palate and had significantly longer upper airway dimensions. Tracheal length was measured in 50 normal children breathing spontaneously under general anaesthesia and was found to correlate best with body weight. Strong positive correlation with height was also found. Data from normal children in these two studies were used to calculate the distance from lips to mid-trachea to determine optimal length for a tracheal tube. Previously published data on airway lengths in children are reviewed.